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Good Manufacturing Practice
The purpose of Good Manufacturing Practice (GMP) is to ensure that products are consistently produced according to the appropriate quality standards.
The reliability of the quality of products is guaranteed by controlling the five critical parameters: manpower, environment, equipment, methods, materials.
Good Pharmacovigilance Practices
Good Pharmacovigilance Practice (GVP) is a quality standard for monitoring the safety of medicines and if necessary, taking action to reduce the risks and increase the benefits of medicines. It ensures the detection, collection, assessment, understanding, and prevention of adverse effects with medicinal products.
Group sequential design
Group sequential design is an example of a statistical approach in clinical trial design. It means that the sample size of the trial is not fixed in advance, and data is sequentially evaluated as it is collected. This is known as interim analysis, and might be carried out at several points in time. The trial can be stopped when significant results are seen, or if the interim analysis shows that there are safety concerns, or that the trial will not in fact be able to give a significant result. In this case no more recruitment of patients or further sampling from the patients involved will occur.
Before the trial starts, the 'stopping rule' (i.e. the reason for stopping) must be documented and explained. The stopping rule is a description of exactly what the interim analysis must show to cause the trial to be stopped.
Group sequential analysis can lead to a conclusion much earlier than would be possible with a classical design. It can therefore save time and resources, and reduces the exposure of patients to inferior treatments.
If a group of trial participants receiving a placebo are monitored/followed up from the moment they enrol in a trial, but the treatment for another group of trial participants does not begin straight away, this time lag can cause bias in the trial. This particular type of bias is called 'guarantee-time bias'.
Guarantee-time bias means that the participants in the treatment arm will only be monitored/followed up if they survive (or, for example, do not have symptoms that the treatment aims to prevent) for the whole of the time lag. Any that do not will be excluded from the trial, and this means the treatment arm is selected on a different basis to the placebo arm.
The easiest way to avoid guarantee-time bias is to use matching. Participants in the treatment arm and the placebo arm are individually matched. If a participant in the treatment arm has to wait 30 days to begin the trial, they are matched with a placebo participant who has also survived or survived without symptoms for 30 days since enrolment. This is also known as establishing matched pairs.